Speed boat



March 4, 1930.` H. L. BRowNBAcK 1,749,017

SPEED BOAT l Enea sept. 18. 1925 Patented Mar. 4, 1930 UNITED, STATESPATENT vOFFICE: I

HENRY LOWE BROWNBACK,-OF NORRISTOWN, PENNSYLVANIA, ASSIGNOR TO BROWN-BACK MOTOR LABORATORIES, INC., OF NEW YORK, N. Y., A CORPORATION OF NEW'YORK SPEED BOAT Application led September 18, 1925. Serial No. 57,135.

. surface of said hull instead of being simply fair comprising anaerodynamic plane formed substantially to an aerofoil curve eX- tendingfrom bow to stern. Thus, in speeding up, the hull will have the supportof the i hydrodynamic plane or series of planes on the bottom surfacewhich have comparatively high lift at low speeds and high resistance athigh speeds, and as soon as the boat attains suflicient speed, the hullwill be supported for the most part by the lift of the aerodynamic topsurface caused by the rarification of the air above said surface, Justenough of the bottom surface touching the water to provide properbalance.

I will explain the invention with reference to the accompanying drawingwhich illustrates several practical embodiments thereof to enable othersfamiliar with the art to adopt and use the same, and will summarize inthe claims the essentials of the invention, the novel features ofconstruction, and novel combinations of parts, for which protection isdesired.

In said drawings Fig. 1 is a side elevation of a speed boat of thewater-drive type, embodying my invention.

Fig. 2 is a top plan view thereof.

' Fig. 3 is a section on the line 3-3, Fig. 2.

Fig. 4 is a side elevation of a speed boat of the air-drive typeembodying my invention. Fig. 5 is a top plan view of the boat shown inFig. 4.

As shown, the boat is preferably substantially rectangular in plan, thewidth thereof being relatively great compared with its length. Thebottom surface of the boat is preferably a hydrodynamic plane or seriesof planes, and as shown the bottom surface is preferably stepped as atla, the forward deeper portion 1b of the hull being curved upwardly atthe bow, as at 1". The rear portion 1l of the bottom surface isshallower than the front portion 1", and the rear end of the bottomsurface 1d is preferably stepped as atv 1, the portion 1t of the bottomin rear of the stepped portion 1 sloping upwardly and rearwardly to meetthe top 2 of the hull.

The bottom surface is designed to support the weight of the boat byhydrodynamic reaction, the hydrodynamic planes 1b, 1d, havingcomparatively high lift at low speeds and high resistance at highspeeds. The bottom of the hull however may be of any other type whichwill assist the hull in gliding over the surface of the water.

The top surface 2 of the'boat is preferably rectangular in plan, andinstead of be'- ing simply fair is built to aerodynamic form, that is, asection taken through the hull from bow to stern, will give a top linehaving a true aerofoil curve, whereby as lthe boat attains suflicientspeed the hull will be supported for the most part by the lift of the'aerodynamic top surface 2, inst enough of the lower surface touchingthe water to provide balance, about 90-95% of thetotal lift of the hullbeing caused by the rarification of air above the top surface 2.

The front end of the top surface 2 is preferably rounded, as at 2, tomeet the upwardly curved portion 1c of the bottom surface. Asdiagrammatically shown in Fig. 3, the hull ofthe boat is preferablybuilt on a system of trusses 3 similar to an aeroplane wing, andcock-pits 2b may be provided in the top surface 2, but should be made assmall as possible 'so as to maintain a maximum areaJ to the -top surface2.

In Fig. 1, the hull is shown as being of water-driven type and houses anengine or motor 4, gear shift 4a, and the propeller shaft The hullconstruction of the air-drive type, shown in Figs. 4 and 5, issubstantiall identical with the construction shown in igs. 1 to 3inclusive, except that the pivot iin 7 is 5 placed at the rear end ofthe section l" of t e bottom surface, and the rudder 8 is located at therear end of the hull, and controlled by the steering wheel 8a (Fig. 5).Furthermore the engine or motor 9 is placed upon t rear 10 end of thetop surface 2 with the propeller 9 well above the surface of the water.

The air and water drive types of hulls however operate in substantiallythe same manner. At low speeds, with low resistances,

suiicient under surface is provided to react against the water and startthe boat gliding and to set the aerodynamic top surface Q'at the bestangle to exert lift on the hull causin the hull to gather speed with aminimum o drag. As soon as the top surface 2 exerts lift on the hull achange in the position of the center of lift of the hull will takeplace, which will set the angle of incidence of the aerodynamic topsurface 2 to give the maximum of lift with the minimum of drift, and soplace the bottom surface that it will exert but little actual lift butwill glide with little resistance and act as a pressure shifter andbalancer. r

Without the aerodynamic top surface 2 in an hydrodynamically supportedhull, of usual type, the bottom surface would exert the entire lift, butwith my thick section aerofoil top surface, the top surface will exertfrom 90-95% of the total lift, my boat therefore utilizing the best ofboth reactions, resulting in a great saving in power, or an increase inspeed with the same power, since the water surface has a lift-drag ratioof from 4-1 to 7-1, and the aerodynamic surface has a lift drag ratio ofabout 18-1.

I d0 not limit my invention to the exact forms shown in the drawing, forobviously changes may be made therein within the scope of the claim.

/ I claim:

A water borne craft comprising a hull of truss construction,substantially rectangular in plan, having an aerodynamic upper sur faceconforming substantially with an aero- "foil curve extending the entirelength of the hull from bow to stern, and having a stepped hydrodynamicbottom surface of corresponding length; said hull having a relativelysmall cock-pit set therein flush with the upper surface; and meansassociated with the hull for propelling the same.

In testimony that I claim the foregoing as my own, I aiiix my signature.

a HENRY LOWE BROWNBACK.

